A KSHV microRNA Directly Targets G Protein-Coupled Receptor Kinase 2 to Promote the Migration and Invasion of Endothelial Cells by Inducing CXCR2 and Activating AKT Signaling

Abstract

Kaposi's sarcoma (KS) is a highly disseminated angiogenic tumor of endothelial cells linked to infection by Kaposi's sarcoma-associated herpesvirus (KSHV). KSHV encodes more than two dozens of miRNAs but their roles in KSHV-induced tumor dissemination and metastasis remain unknown. Here, we found that ectopic expression of miR-K12-3 (miR-K3) promoted endothelial cell migration and invasion. Bioinformatics and luciferase reporter analyses showed that miR-K3 directly targeted G protein-coupled receptor (GPCR) kinase 2 (GRK2, official gene symbol ADRBK1). Importantly, overexpression of GRK2 reversed miR-K3 induction of cell migration and invasion. Furthermore, the chemokine receptor CXCR2, which was negatively regulated by GRK2, was upregulated in miR-K3-transduced endothelial cells. Knock down of CXCR2 abolished miR-K3-induced cell migration and invasion. Moreover, miR-K3 downregulation of GRK2 relieved its direct inhibitory effect on AKT. Both CXCR2 induction and the release of AKT from GRK2 were required for miR-K3 maximum activation of AKT and induction of cell migration and invasion. Finally, deletion of miR-K3 from the KSHV genome abrogated its effect on the GRK2/CXCR2/AKT pathway and KSHV-induced migration and invasion. Our data provide the first-line evidence that, by repressing GRK2, miR-K3 facilitates cell migration and invasion via activation of CXCR2/AKT signaling, which likely contribute to the dissemination of KSHV-induced tumors.

Kaposi sarcoma–associated herpesvirus: immunobiology, oncogenesis, and therapy

“…Thus far, miRNA studies have been constrained by sensitivity limits for detection of individual miRNAs and for the discovery of miRNA-target interactions. Targets with functions that seem to befit the biology of B cell development, endothelial cell differentiation, and KSHV (such as BACH1, xCT, MAF, and others) have been individually validated (132)(133)(134). These are by no means the only targets, and it is anticipated that additional targets will be identified in the future.…”

Periodic Mechanical Stress Induces Extracellular Matrix Expression and Migration of Rat Nucleus Pulposus Cells Through Src-GIT1-ERK1/2 Signaling Pathway

“…For cell samples, immunoprecipitation was performed according to a previous study [17]. Briefly, NP cells were collected, rinsed twice with cold phosphate buffered saline (PBS), and lysed in Lysis/Wash buffer (Beyotime Institute of Biotechnology, China), and supplemented with phenylmethylsulfonyl fluoride (PMSF; Beyotime Institute of Biotechnology, China).…”

Development of Inflammatory Immune Response-Related Drugs Based on G Protein-Coupled Receptor Kinase 2

“…Of the 12 viral KSHV-encoded miRNAs that function as regulators by maintaining viral latency and inhibiting viral lytic replication, the expression of miR-K3 in latent KSHV-infected cells can suppress both viral lytic replication and gene expression. miR-K3-targeted GRK2 can promote the migration and invasion of endothelial cells by inducing CXCR2 expression and activating AKT signaling, which was initially identified as a Ser/ Thr kinase implicated in the regulation of GPCRs with arrestins and the modulation of cell motility by the complex [70].…”